The present invention relates to a magnetic disk assembly for use in a data processing apparatus or similar apparatus and, more particularly, to a magnetic disk assembly having a stack of magnetic disks capable of recording a great amount of data and supported by a clamp ring.
One of conventional magnetic disk assemblies is disclosed in Japanese Patent Laid-Open Publication No. 2-292786. The disk assembly has a plurality of magnetic disks and a plurality or spacer rings alternating with each other. The spacer rings each separates the nearby disks and adjoins the inner edges of the disks. An annular groove is formed in the outer circumference of each spacer ring. A spindle hub has a flange portion at the bottom thereof. The flange portion is formed with a first annular support surface contacting the lowermost or bottom disk. A clamp ring has a second annular support surface facing the first support surface of the spindle hub and contacting the uppermost or top disk. The disks and spacer rings alternating with each other are supported by the first and second support surfaces of the spindle hub and clamp ring. The clamp ring is heated, fitted on the outer periphery of the spindle hub, and then cooled off. As a result, the clamp ring is affixed to the spindle hub in a predetermined position, thereby fastening the stack of disks and spacer rings.
However, the conventional disk assembly described above has some problems yet to be solved, as follows. The clamp ring is affixed to the spindle hub by shrinkage fit. Specifically, the clamp ring is heated to a high temperature so as to increase the inside diameter due to expansion. In this condition, it is coupled over the spindle hub and then cooled off. As a result, the inside diameter of the clamp ring is reduced due to shrinkage, fastening the clamp ring to the spindle hub. Hence, once the disks alternating with the spacer rings are affixed to the spindle hub by the clamp ring, they cannot be removed from the hub. It follows that when scratches or similar defects are found, even on part of the disks, the entire disk assembly must be replaced or discarded. This increases the production cost of the disk assembly to a critical degree.